HomeMy WebLinkAboutCity of Renton Wet Season Notes.docxCity of Renton Wet Season Notes
The following provisions for wet season construction are detailed in Appendix D of the 2017 Renton Surface Water Design Manual Please ensure your site is protected and complies with
the special provisions outlined below. The wet season lasts from October 1st through April 30th. The basic requirements are:
1. The allowed time that a disturbed area can remain unworked without cover measures is reduced to two (2) days, rather than seven (7) days.
2. Stockpiles, steep cut, and fill slopes are to be covered or protected with mulch, sod, plastic covering, jute mat etc. if left unworked for more than 12 hours.
3. Cover materials (plastic, matting, etc.) sufficient to cover all disturbed areas, shall be stockpiled and available on site.
4. All areas that are to be unworked during the wet season shall be seeded within one week of the beginning of the wet season. Seeded should be completed by September 23rd.
5. Mulch is required to protect all seeded areas.
6. Fifty linear feet of silt fence (and the necessary stakes) per disturbed acre must be stockpiled on site.
7. Properly installed silt fencing is mandatory along the downslope of all disturbed areas of the site. Perimeter protection filters runoff and reduces the amount of sediment that may
leave the site.
8. Sediment retention is required unless no offsite discharge is anticipated for the specified design flow.
9. Construction road and parking lot stabilization are required for all sites unless the site is underlain by coarse-grained soil.
10. Surface water controls are required unless no offsite discharge is anticipated for the specified design flow.
11. Phasing and more conservative BMPs must be evaluated for construction activity near surface waters.
12. Any runoff generated by dewatering shall be treated through construction of a sediment trap when there is sufficient space or by releasing the water to a well vegetated, gently sloping
area. Since pumps are used for dewatering, it may be possible to pump the sediment-laden water well away from the surface water so that vegetation can be more effectively utilized for
treatment. A straw bale filter shall be placed around the discharge from the dewatering pump. If there is not space for a sediment trap or 25 feet of suitable vegetation, other filtration
methods shall be required.
13. The frequency of maintenance review should be increased from weekly to daily where warranted.
The City of Renton is committed to effective erosion and sediment control practices. Please be advised if voluntary action is not taken to properly protect your site, a civil infraction
citation can be issued and civil penalties will be assessed for each and every day the infraction continues. Fines under Renton Municipal Code, Title 1, Chapter 3, are as follows: First
three (3) days of violation at $100 a day; second three (3) days of violation at $200 a day; third (3) days of violation at $300 a day and $500 a day for each additional day thereafter.